The present invention relates to a data recording apparatus and a data recording method for recording audio-visual data to a disk drive.
In recent years, there has been rapid improvement in the performance, such as recording capacity and transfer speed, of a magnetic disk drive, an optical disk drive, and the like. In particular, the improvement is remarkable in the performance of a hard disk drive (HDD), which has accelerated the frequent use of such an HDD in the recording and reproducing of audio-visual data.
Meanwhile, with the progress in the development of a digital interface, it has become frequent that a digital video device (abbreviated as DV device hereafter), such as a digital VCR, is equipped with a digital interface in accordance with IEEE1394 Standard (abbreviated as an IEEE1394 interface hereafter). The IEEE1394 Standard prescribes the isochronous transfer scheme in which digital audio-visual data is transferred continuously. With regard to the transfer scheme using the IEEE1394 interface, IEC61883 prescribes, for example, a transfer scheme for the audio-visual data in DV format.
In particular, many systems have been proposed recently in which a DV device equipped with an IEEE1394 interface is connected to a personal computer (abbreviated as a PC hereafter) thereby editing the video data shot with a DV device.
The editing process in such a system is carried out in the following procedure:
1. Audio-visual data shot with a DV device is taken into an HDD built into a PC (abbreviated as a PC-installed HDD hereafter),
2. The audio-visual data taken into the PC-installed HDD is processed so that the length of scene are adjusted, the scenes are reorganized, video effects are applied, and so on. Then, the data is saved in the PC-installed HDD again, and
3. The processed audio-visual data is read out from the PC-installed HDD and written back through the IEEE1394 interface onto the DV device.
However, during the third process of the above-mentioned editing system, “frame dropping” has frequently occurred on the PC side. The frame dropping is caused by that the audio-visual data to be written in back to the DV device can not be read out from the PC-installed HDD in a predetermined time, for example, when another application software accesses the PC-installed HDD during the process of writing back onto the DV device, when the PC-installed HDD has a slow readout speed, or when the PC-installed HDD suffers from a strong shock or vibration. In case of the occurrence of frame dropping, the PC performs the process of re-transmitting, to the IEEE1394 interface, the video frame data read out just previously from the PC-installed HDD (this process is referred to as a frame re-transmission control process hereafter). By the frame re-transmission control process, the PC continues to transmit the audio-visual data in the DV format to the DV device continuously.
In case that all of the audio-visual data underwent the frame re-transmission control process owing to the occurrence of frame dropping in the PC as a transmitting device is recorded in the DV device as a receiving device, as described above, there has been a problem that the recording time of the audio-visual data recorded in the DV device becomes longer than that of the original audio-visual data saved in the PC-installed HDD.